Depending on your workspace privacy settings and the permission settings for individual workspace items, some content will be visible to all users of Futures. This can be either through the Futures site-wide search or shared links. This article will explain how the workspace privacy settings work in relation to content discoverability.
Open workspaces - If your workspace is 'Open' in the privacy settings then content that is visible to 'Users' will appear in the Futures search results for all registered users of Futures.
Restricted workspaces - If your workspace is 'Restricted' in the privacy settings then content that is visible to 'Users' will appear in the Futures search results for all registered users of Futures.
Private workspaces - If your workspace is 'Private' in the privacy settings then items from your workspace will not be visible in the Futures site-wide search and cannot be shared with users who are not members of your workspace.
Confidential workspaces - If your workspace is 'Confidential' in the privacy settings then items from your workspace will not be visible in the Futures site-wide search and cannot be shared with users who are not members of your workspace.
For more detail on workspace privacy settings please see Workspace privacy and how to change it.
For more detail on applying permission settings to individual workspace items please see Permissions on Futures and how to set them.